With the recent diversified hair fashion, there arises great demand for hairstyling agents with various functions. Among all, it has been strongly required that a definite hair style is retained over a long period of time under various circumstances, in particular, under a high humidity or in strong winds.
It has been a practice to add various polymers to hairstyling agents so as to impart a strong set-retaining power. Examples of the polymers commonly employed for such the purpose include the following ones:
vinylpyrrolidone/vinyl acetate copolymer (PVP/VAE 335, manufactured by ISP); PA1 vinylpyrrolidone/dimethyl aminoethyl methacrylate copolymer (Copolymer 845, manufactured by ISP); PA1 methyl vinyl ether/monoalkyl maleate copolymer (Gantrez ES225, manufactured by ISP); and PA1 chitosan/dl-pyrrolidonecarboxylate (Kytamer PC, manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.).
Each of these polymers has a high modulus of film elasticity of 1.times.10.sup.8 Pa or more (20.degree. C., relative humidity 65%).
However, when the hair is set with a hairstyling agent containing such a polymer capable of forming a highly elastic film, there arise some problems. That is, the hair becomes stiff and the hairstyle loses natural feel both in appearance and texture.